1. Field of the Invention
The invention relates to a method and an apparatus for the manufacture of filler sticks for cosmetic sticks or the like, the filler stick being cast into a casing which is inserted in a mold and the liquid casting compound rigidifying in the casing and in the mold, respectively.
2. Background Art
A method of the generic type is known from German patent 38 35 680. In the known method, the casing is a plastic molding of the type of a tube which is slit along its generated surface and is inserted in a horizontal holder in such a way that a continuous front plate of the holder covers the plastic moldings so that only the slit is left free for the filler stick compound to be filled in. Horizontal casting of this type ensures an optimum structure of the filler stick, but the operating speed is not satisfactory.
DE 40 16 474 specifies a method and an apparatus according to which the casings, which are to be filled with the casting compound, are lodged to be driven in rotation and the free flowing compound is forced out of a reservoir and into the casings by the action of centrifugal force.
DE 27 18 957 C3 and DE 40 05 894 A1 teach to fill the filler stick compound via a nozzle into a vertically positioned casing from the rearward end thereof. Problems arise in particular in the case of comparatively long and thin casings due to the fact that any inclusion of air in the casing must be carefully avoided, i.e. a possibility must be created for the evacuation of air during the casting job.
In order to come up to this problem, it is known to proportion the liquid filler stick material by the aid of a kind of injection needle at some radial play towards the inside wall of the casing, the metering nozzle being inserted inside the casing as far as to the bottom thereof and then being lifted successively in accordance with the rising level within the casing by means of comparatively complicated kinematics. Consequently, the air can escape between the casting nozzle and the wall of the casing.
This mode of operation requires comparatively complicated mechanical machines to be provided for the accurate insertion of the casting nozzle, accurate positioning being necessary in the radial direction as well as accurate change of position in the vertical direction, depending on the filling level of the casing.
DE 43 03 563 teaches in the casing to arrange a closing member, which is in the vicinity of a first end of the casing at the beginning of the casting job and, as the casting process proceeds, is moved as far as into the vicinity of the second end of the casing, corresponding to the quantity of liquid filler stick compound supplied to the casing.
These known methods have the drawback that a core of a filler stick is produced in dependence on gravity, that soiling of the mold occurs and that structural flaws, air cavities and shrinkholes can be observed, conditioned by varying geometries and volumes of the metering chambers and the filler sticks as well as by a rough inner surface and by the tilting of the filler stick tube directly after filling.